/* This file is part of MyRename
 * Copyright (C) 2005-2009 Kai-Chieh Ku (kjackie@gmail.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

//////////////////////////////////////////////////
// CMemDC - memory DC
//
// Author: Keith Rule
// Email:  keithr@europa.com
// Copyright 1996-2002, Keith Rule
//
// You may freely use or modify this code provided this
// Copyright is included in all derived versions.
//
// History - 10/3/97 Fixed scrolling bug.
//               Added print support. - KR
//
//       11/3/99 Fixed most common complaint. Added
//            background color fill. - KR
//
//       11/3/99 Added support for mapping modes other than
//            MM_TEXT as suggested by Lee Sang Hun. - KR
//
//       02/11/02 Added support for CScrollView as supplied
//             by Gary Kirkham. - KR
//
// This class implements a memory Device Context which allows
// flicker free drawing.
#pragma once

class CMemDC : public CDC {
public:
	CMemDC(CDC* pDC, LPCRECT pRect/* = NULL*/)
		: CDC()
	{
		ASSERT(pDC != NULL); 

		// Some initialization
		m_pDC = pDC;
		m_oldBitmap = NULL;
		m_bMemDC = !pDC->IsPrinting();
		m_bFlushed = false;

		// Get the rectangle to draw
		if (pRect == NULL) {
			pDC->GetClipBox(&m_rect);
		} else {
			m_rect = *pRect;
		}

		if (m_bMemDC) {
			// Create a Memory DC
			CreateCompatibleDC(pDC);
			pDC->LPtoDP(&m_rect);

			m_bitmap.CreateCompatibleBitmap(pDC, m_rect.Width(), m_rect.Height());
			m_oldBitmap = SelectObject(&m_bitmap);

			SetMapMode(pDC->GetMapMode());

			SetWindowExt(pDC->GetWindowExt());
			SetViewportExt(pDC->GetViewportExt());

			pDC->DPtoLP(&m_rect);
			SetWindowOrg(m_rect.left, m_rect.top);
		} else {
			m_bPrinting = pDC->m_bPrinting;
			m_hDC       = pDC->m_hDC;
			m_hAttribDC = pDC->m_hAttribDC;
		}

		// Fill background 
		FillSolidRect(m_rect, pDC->GetBkColor());
	}

	virtual ~CMemDC()
	{
		Flush();
	}

	void Flush()
	{
		if (!m_bFlushed){
			m_bFlushed = true;
			if (m_bMemDC) {
				// Copy the offscreen bitmap onto the screen.
				m_pDC->BitBlt(m_rect.left, m_rect.top, 
					m_rect.Width(),  m_rect.Height(),
					this, m_rect.left, m_rect.top, SRCCOPY);            

				//Swap back the original bitmap.
				SelectObject(m_oldBitmap);
			}
			else
				m_hDC = m_hAttribDC = NULL;  
		}
	}

	CMemDC* operator->() 
	{
		return this;
	}
	operator CMemDC*() 
	{
		return this;
	}
private:       
	CBitmap    m_bitmap;        // Offscreen bitmap
	CBitmap*   m_oldBitmap;		// bitmap originally found in CMemDC
	CDC*       m_pDC;           // Saves CDC passed in constructor
	CRect      m_rect;          // Rectangle of drawing area.
	BOOL       m_bMemDC;        // TRUE if CDC really is a Memory DC.
	bool	   m_bFlushed;
};

class MemDC
{
public:
	MemDC(HWND hWnd) //like CPaintDC
		: m_hDC(0), m_hOldDC(0), m_hBitmap(0), m_hOldBitmap(0), m_bFlushed(false), m_hWnd(hWnd)
	{
		_ASSERT(hWnd);
		BeginPaint(m_hWnd, &m_ps);
		Init(m_hOldDC = m_ps.hdc, &m_ps.rcPaint);
	}

	MemDC(HDC hDC, LPRECT pRect)
		: m_hDC(0), m_hOldDC(hDC), m_hBitmap(0), m_hOldBitmap(0), m_bFlushed(false), m_hWnd(0)
	{
		Init(hDC, pRect);
	}

	virtual ~MemDC()
	{
		Flush();
	}

	void Flush()
	{
		if (!m_bFlushed) {
			m_bFlushed = true;
			//Swap back the original bitmap.
			if (m_hBitmap) {
				// Copy the offscreen bitmap onto the screen.
				BitBlt(m_hOldDC, m_rect.left, m_rect.top, 
					m_rect.right - m_rect.left, m_rect.bottom - m_rect.top,
					m_hDC, m_rect.left, m_rect.top, SRCCOPY);

				SelectObject(m_hDC, m_hOldBitmap);
				DeleteObject((HGDIOBJ) m_hBitmap);
			}
			if (m_hDC && m_hDC != m_hOldDC)
				DeleteDC(m_hDC);
			if (m_hWnd)
				EndPaint(m_hWnd, &m_ps);
		}
	}

	operator HDC() const
	{
		return m_hDC;
	}

	HDC m_hDC;
private:
	void Init(HDC hDC, LPRECT pRect)
	{
		_ASSERT(hDC);

		// Get the rectangle to draw
		if (pRect == NULL) {
			GetClipBox(hDC, &m_rect);
		} else {
			m_rect = *pRect;
		}

		// Create a Memory DC
		m_hDC = CreateCompatibleDC(hDC);
		_ASSERT(m_hDC);
		LPtoDP(hDC, (LPPOINT) &m_rect, 2);

		if (m_hBitmap = CreateCompatibleBitmap(hDC, m_rect.right - m_rect.left, m_rect.bottom - m_rect.top)) {
			m_hOldBitmap = (HBITMAP) SelectObject(m_hDC, m_hBitmap);

			SetMapMode(m_hDC, GetMapMode(hDC));

			SIZE size;

			GetWindowExtEx(hDC, &size);
			SetWindowExtEx(m_hDC, size.cx, size.cy, NULL);

			GetViewportExtEx(hDC, &size);
			SetViewportExtEx(m_hDC, size.cx, size.cy, NULL);
		}
		else {
			_ASSERT(0);
			ATLTRACE(LastErrorMsg());
			DeleteDC(m_hDC);
			m_hDC = hDC;
		}

		DPtoLP(hDC, (LPPOINT) &m_rect, 2);

		SetWindowOrgEx(m_hDC, m_rect.left, m_rect.top, NULL);

		// Fill background
		COLORREF clr = GetBkColor(hDC);
		SetBkColor(m_hDC, clr);
		ExtTextOut(m_hDC, 0, 0, ETO_OPAQUE, &m_rect, NULL, 0, NULL);
	}

	HDC m_hOldDC;
	HBITMAP m_hBitmap;
	HBITMAP m_hOldBitmap;
	bool m_bFlushed;
	RECT m_rect;
	HWND m_hWnd;
	PAINTSTRUCT m_ps;
};

